This invention relates to an adaptor assembly for removably attaching a second, traction wheel to each of the conventional driven wheels of a material-handling implement such as a forklift truck.
Forklift trucks and the like are provided with solid-rubber tires and very hard pneumatic tires which are designed primarily for operation on hard or well-packed surfaces. Such tires have very little flexibility and, as a result, provide poor traction if operated on nonpaved surfaces and are substantially useless if the surface is inclined.
Accordingly, the present invention provides an adaptor assembly for removably attaching a second wheel to each of the forklift driven wheels with the second wheel having a tire maintained at a relatively low pressure to provide good traction for the forklift. An adaptor assembly according to the present invention is designed to function with a conventional automotive tire rim and conventional automotive or turf tire as the traction wheel.
The addition of auxiliary traction tires to a forklift adds considerable width to the vehicle and makes it less maneuverable. Because a forklift is typically primarily used indoors on hard surfaces, where the auxiliary traction tires are not desirable, it is important that the tractor tires be very easily mounted to and removed from the forklift. The present invention provides a traction wheel assembly that may be easily and quickly mounted to the forklift when additional traction is desired and removed therefrom when the forklift is returned to normal service.
Because the purpose of the second wheel is for traction only, the structure of the adaptor assembly is primarily directed to transmitting torque from the driven wheel to the traction wheel rather than in supporting a substantial portion of the weight of the forklift on the second wheel. Accordingly, the present invention provides an adaptor assembly that requires minimum material mass and, therefore, minimizes the weight added to the vehicle.
In a conventional forklift truck, the driven wheels are the front wheels. A gear assembly is therefore normally included within the hub to which each of the driven wheels is attached. It is therefore necessary that this hub be readily accessible for service and maintenance. The present invention provides an adaptor assembly for removably mounting a second, traction wheel to each of the drive wheels while allowing ready access to the hubs of the drive wheels.